Just to throw a little gasoline on the George Gilder "Dark Fiber" discussion around here, I found a huge, spiffy trove of Gilderama at: http://www.computer.org/internet/9701/gilder9701.htm Wherein the esteemed (at least I do ;-)) Mr. G says:
Remember that the fibersphere I've written a lot about is based on wavelength-division multiplexing of tremendous amounts of bandwidth, which can serve as a substitute for switches with all optical repeaters. And by the way they've just developed fluoro-zirconate repeaters that can handle the whole bandwidth of fiber. I don't know whether this technology will actually prove out or not, but for the first time they have demonstrable all-optical amplifiers that can handle the entire intrinsic bandwidth of fiber, which is quite an amazing development in just a year or two. The erbium-doped fiber amplifiers top out at 4.5 terahertz, so they can't accommodate the potentially 25-75 terahertz that every fiber, theoretically, could hold.
What this means, of course, is that (kind of, as CDMA etc., counts a switching, I guess) like wireless, electromagnetic bandwidth, some day you'll have huge glops of non-switched fiber bandwidth to play with. In theory, at least, everyone gets a color, or frequency, and they listen on that frequency for their inbound stuff. If you want to send someone something, you literally tune them in and send it. Actually, I see these frequencies using CDMA carrier waves when it eventually happens, but you get the idea. The implications for cryptography are rather cool. I don't *think* these doped optical amplifiers interfere with so-called quantum cryptography (not to be confused with quantum computing, of course). If I remember my SciAm back issues, quantum crypto is cool, because if anyone touches the signal from Alice to Bob they're detected immediately. Or, is it that the signal drops? Can't remember which. Anyway, you need uninterrupted fiber to do QC, and that's what you have with optical non-switched amplification, whether you're disturbing the photons is another story. Anyone here know for sure? I remember discussion about this, but I don't remember the answer. Cheers, Bob Hettinga ----------------- Robert Hettinga (rah@shipwright.com), Philodox e$, 44 Farquhar Street, Boston, MA 02131 USA "Never attribute to conspiracy what can be explained by stupidity." -- Jerry Pournelle The e$ Home Page: http://www.shipwright.com/rah/